Balanced slide-valve.



J. T. WILSON.

I BALANGBD SLIDE VALVE.

APPLIOATIGN FILED JULY 24, 100e.

Patented Mar. 9, 1909.

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JOHN THOMAS WILSON, OF JERSEY SHORE, PENNSYLVANIA.

BALANCED SLIDE-VALVE.

Speccaton of Letters Patent.

Application led July 24, 1906.

Patented March 9, 1909.

Serial No. 327,480.

To all 'whom 'Lt may concern:

Be it known that 1, JOHN T. VILsoN, a citizen of the United States,residingV at Jersey Shore, in the county of Lycoming and State ofPennsylvania, have invented new and useful improvements in BalancedSlide-Valves, of which the following is a specication.

rThe object of my invention is the provision of improved means forcontrolling the admission of motive fluid to the cylinder of an engineand its discharge therefrom, said means to embrace a reciprocating valveof light weight, means for holding the valve upon its seat when in itscentral position by a predetermined pressure so it can move easily andstill not allow the escape of motive iiuid, and means which shallcompensate for the variation in pressure when the valve is moved fromits central position to .its two alternate wide open positions at theends of its strokes .in opposite directions.

The invention consists in certain novelties of construction andcombinations of parts as hereinafter set forth.

r1"he accompanying drawings illustrate one complete example, and onemodification, of the physical embodiment of the invention constructedaccording to the best modes l have so far devised for the practicalapplication of the principle.

Figure 1 is a longitudinal section in elevation of a steam chest andpart of a cylinder, showing the relative location of the parts of thedevice. Fig. 2 is a cross section taken at right angles to Fig. 1. Fig.3 is a top plan view of the valve proper. Fig. 4 is a top plan view ofthe balance plate on a reduced scale. Fig. 5 is a top plan view of thepressure plate on a reduced scale. Fig. 6 is a bottom plan view of Fig.5. Figs. 7 and 8 show edge and side views of the packing strips. Fig. 9is a section on line a@ Fig. 6, showing a channel and an end packingstrip in elevation therein. Fig. 10 and 11 are views similar to Figs. 1and 2, but showing the packing strips located in the balance plate.

Referring to Figs. 1 to 9, the numeral 1 designates the removable steamchest cover; 2, the end walls of the steam. chest; 3, an opening for thevalve stem; L1, the cylinder; 5, the raised valve seat; 6, the steamadmission ports to the cylinder; 7, the exhaust steam port or cavity incommunication with the atmosphere; 8, the end walls of the i 'of thepressure plate;

valve; 9, the side walls; 10, a series of admission ports or passagesthrough the side walls; 11, a series of exhaust ports or passagesthrough the valve; 12, ribs joining the sides of the valve; 13, seatsfor the yoke; 141-, the yoke; 15, the valve stem; 16, the balance plate;17, projecting lugs which loosely engage the inner surfaces of the steamchest walls and hold the plate in central position; 18, two series ofholes through the central part of the plate; 19, two longitudinalpockets in the under surface of the plate; 20, two series of holes orpocket ports through the plate and in line with the pockets; 21, thepressure plate; 22, lugs orbosses projecting from the top surface of theplate and which match similar perforated bosses 23 upon the innersurface of the steam chest cover; 211, threaded holes in the lugs of theplate; 25, threaded bolts which pass through the steam chest cover andbosses thereupon and engage the threaded lugs upon the top surface ofthe pressure plate; 26, channels in the under surface of the plate oneat each end; 27, end packing strips in the channels, each strip havinga' widened portion 28 near each end; 29, two parallel channels in theunder surface of the plate at each side; 30, side packing strips in thesaid channels; 31, spaces or areas at opposite sides ofthe plateinclosed by the packing strips, each of said spaces being open to apocket 19 in the balance plate by way of the pocket ports 2O in theplate; 32, pockets in the under surface 33, holes from said pockets tothe bottoms of the inner channels 29 whereby steam can pass beneath theinner packing strips 30 and force them outwardly and into contact withthe top surface of the balance plate; and 34 is one of the springslocated in each of the channels 26 and 29 and back of the packing strips27 and 30, as shown in Fig. 9, which springs force the said stripsoutwardly against the balance plate.

By reference to Fig. 9 it will be seen that the end channel 26 and theouter channel 29 are open to the steam chest at points 35 and 36respectively so steam can pass back of the strips 27 and outer strips 30and force them against the balance plate. The widened portion 2S ofstrip 27 however covers the end of inner channel 29, as shown, so steamcannot enter except by way of the holes 33 as before specified.

The modified form of construction shown in Figs. 10 and 11 is identicalwith that shown in the other figures, except that the packing strips 27and 30 are located within channels formed in the top surface of thebalance Vplate and the projecting edges of the strips bear against theunder surface of the pressure plate. The inclosed areas 81 at theopposite sides of the balance plate are present and formed insubstantially the same way; and the mode of operation is the same as inthe first example.

ItV will be observed that both faces of the valve are parallel and ofidentical construction; that the under surface of the balance plate isof the same area and shape as the raised valve seat, and the pockets 19of the same area as the steam admission ports to the cylinder; that thebalance plate can rock slightly and lift to relieve the cylinder whenthe engine is drifting, inasmuch as the plate is located a shortdistance from the under surface of the pressure plate; and that thepacking strips are stationary. The inner area of the top surface of thebalance plate bounded by the end packing strips 27 and outer strips 30which is to be excluded from the pressure of steam within the chest isdetermined in any given case by experiment. However, the mainrequirement is that the area of the balance plate exterior of'thesepacking strips which is subjected to steam pressure should be suiiicientto hold the valve in place and allow it to move from its centralposition upon a moderate force being applied to theJ valve stem.

Giving attention to one side ofv the valve only, the operation is asfollows: When the valve is moved from the central position shown in Fig.1 to the opening position shown by Fig. 10, steam passes as shown by thearrow O directly downward into the cylinder and also by the arrow l)through the admission passages 10 to the cylinder. At the same timesteam passes as shown by the arrow Q to the inclosed area 31 at the topof the balance plate. Steam pressure upon the top and bottom faces ofthe valve, where it laps the port, and the top and bottom faces of thebalance plate at the edge adjacent the port, is thus equalized. In thewide open position shown in dotted lines, Fig. 1, the balance ispreserved, inasmuch as the top face of the valve at the left has passedout from under the balance plate the same distance its lower face haspassed over the edge of the valve seat. When the valve is moved from thewide open position toward the right, the position of steam cut off isalso shown by Fig. 10. l/Vhen the valve covers the port, the pressureupon the top and bottom faces and upon the top and bottom surfaces ofthe balance plate is obviously constant. As the valve moves farthertoward the right, and reaches the position of exhaust, steam passesdirectly from the port and also by way of the exhaust passages 11 to theexhaust cavity 7. At the same time steam in the inclosed space 31 passesout into the exhaust cavity, thus preserving the balance which otherwisewould be destroyed by the top surface of the valve excluding from steampressure the under surface of the balance plate adjacent the pocket 19therein. f

The operation of the opposite side of the valve is simultaneousalternate as to the admission and of steam.

From the foregoing description taken in connection with the drawings itis clear that l have provided improved means for controlling theadmission of motive iiuid to an exhaustion and identical, but

engine cylinder and its discharge there.V

from, which means are of the character and perform the functions setforth as the object of my invention.

What 1' claim is:

1. The combination with a steam chestand a cylinder provided with avalve seat having steam inlet ports to the cylinder and an exhaust port,of a slide valve, a balance plate, and a pressure plate; packing stripsbeing located between the balance plate and pressure plate to form twoinclosed spaces,

one at each side of the balance plate, and tok exclude from steampressure the central portion of the balance plate; and said balanceplate having ports communicating with the said two inclosed spaceswhereby steam may be admitted to and discharged from said inclosedspaces simultaneously with the admission of steam to and its dischargefrom the cylinder ports. j j

:2. The combination with a steam chest having a removable cover andacylinder provided with a valve seat having steam inlet ports to thecylinderl and an exhaust port, of a slide valve, a balance plate, apressure plate, and bolts for holding the pressure plate relative to theremovable cover; packing strips being located between the balance plateand pressure plate to form two inclosed spaces one at each side of thebalance plate, and to exclude from steam pressure the central portion ofthe balance plate; and said balance plate having ports communicatingwith the said two inclosed spaces whereby steam may be admitted to anddischarged from said inclosed spaces simultaneously with the admissionof steam to and its discharge from the cylinder ports. Y

3. The combination with a steam chest, and a cylinder provided with avalve seat having steam inlet ports to the cylinder, and an exhaustport, of a slide valve a balance plate, and a pressure plate; packingstrips 27 and 30, the said strips 27 being arranged at angles to strips30, and all said strips being located between the balance plate and thepressure plate to form two inclosed spaces, one at each side of thebalance plate7 and to exclude from steam pressure the central portion ofthe balance plate; and said balance plate having ports communicatingwith the said two inclosed spaces whereby upon the reciprocation of theslide valve steam may alternately be admitted to and discharged fromsaid inclosed spaces.

il. The combination with a steam chest7 and a cylinder provided with avalve seat having steam inlet ports to the cylinder and an exhaust portof a slide valve7 a balance plate, and a pressure plate; packing strips27 and 30 being located between the balance plate and the pressure plateand within channels formed within one of the said plates; to form twoinclosed spaces, one at each side of the balance plate, and to excludefrom steam pressure the central por tion of the balance plate; and saidbalance plate being provided with ports communieating with the said twoinclosed spaces; for the purpose set forth.

The combination with a steam chest, and a cylinder provided with a valveseat having steam inlet port-s to the cylinder and an exhaust port of aslide valve, a balance plate; and a pressure plate; packing strips 2Tand 30 located between the balance plate and the pressure plate andwithin channels tonmed in one of said plates; and openings for admittingsteam to the backs of the two strips 27 and the strips 30; said balanceplate having ports communicating with each inclosed space formed at thesides of the balance plate by the said packing strips; in substance asset forth.

6. r)The combination with a steam chest and a cylinder provided with avalve seat having steam inlet ports and an exhaust port; of a slidevalve; a balance plate above said valve; and means `for forming twoinclosed spaces above the balance plate and for eX- cluding from steampressure the central portion of the balance plate, said means embracingend packing strips 27; side packing strips 30, and an element with ahorizontal surface between which surface and the balance plate saidpacking strips are located; said balance plate being provided with portscommunicating with the said two inclosed spaces7 whereby upon thereciprocation of the valve steam may simultaneously be admitted to anddischarged from a cylinder port and one of the inclosed spaces.

7. The combination with a steam chest and a cylinder provided with avalve seat7 of a valve; a balance plate; means for eX- cluding a part ofthe back of the balance plate from the action of steam pressure and forforming a plurality of spaces at the back or' the balance plate, saidmeans embracing straight packing strips which are independent of themovement of the valve; and means for alternately admitting anddischarging steam from the said spaces.

8. lThe combination with a cylinder provided with a valve seat and port,of a valve movable upon the seat; a balance plate in frictional contactwith the valve; means embracing straight packing strips which areindependent of the motion of the valve to form an inclosed space at theback of the balance plate; and means for alternately admitting steam toand discharging steam from said inclosed space simultaneously with theadmission of steam to and its discharge from the port in the cylinder.

ln testimony whereof affix my signature in presence of two witnesses.

JOHN THOMAS l/VLSON.

Viitnesses:

M. L. STAvnR, CORYELL BLACKWELL.

